The present invention relates to a cradle for a film, coating, or sealing rod, in which the rod cradle has a profile that includes a base part, a rod groove, and a body part between them, and in which the rod groove is arranged to receive the rod between lips edging the rod groove, and in which the circumference lying against the rod is formed at least partly of a slider piece of a material other than the material of the base part and the body part. Rod cradles are used in surface-sizing and coating devices. Usually the profile includes at least one liquid groove formed on the bottom of the rod groove.
Usually, the rod cradle is machined, molded, or extruded from a single material. A compromise must then be made between the material requirements.
Finnish patent 111477 (WO00/63494) discloses a coating device for a paper machine, in which the coating cradle is in two parts. The two-part construction permits the rod groove to be made from a material better suited to the operation of the rod, when a flexible material of sufficient strength is used in the body and base parts. However, the solution disclosed is a complex totality. As such, the problems referred to in the patent are still relevant. The wear resistance of the rod cradle will not be satisfactory, if the material must be selected as a compromise with the requirements of the base and body parts. If the rod is installed in a very hard cradle, both the rod and the cradle are in danger of breaking.
In general, widely differing technical demands are placed on the rod cradle, such as                good wear resistance        easy installation of the rod        good slip properties when dry and when lubricated with water, paste, or size        good non-dirtying/release properties        attenuation of vibration        good chemical resistance in the prevailing environmental conditions        
Application publications DE 10045515 and WO 03/078077 disclose the creation of a separate rod-groove component. A rod bed consisting of a slot-like piece, which has, in addition to the rod groove, a water groove for water lubrication, is manufactured from a material with better wear resistance. The body part has a recess of corresponding size for this rod bed, to which the rod bed is locked mechanically. Such a solution is obviously expensive to manufacture, because the rod bed must be made in a completely separate work stage while the recess it requires is machined in its own work stage.
Wear resistance can be improved by surfacing, as is disclosed in PCT publication WO 00/58555. However, the thickness of the surfacing remains so small as to make the result unsatisfactory.